A slide projector shines light through a photographic slide and uses concave and convex lenses to project a larger image of the slide. Building a slide projector means simply constructing a frame or container that will hold the slide, a light source and the lenses so that the light travels through all the pieces correctly. If you don't include a slide tray and just insert and remove slides individually, you can build a projector that is smaller than most.
Instructions
1. Assemble three square frames out of wood. The frames need to be the same size and able to fit either lens and the end of the flashlight. Cut a hole in each piece for one lens and glue the lens into the hole. Attach the flashlight's open end with the lightbulb to the other frame.
2. Make a holding frame for the slides using another square wooden frame. Cut this piece into a square "U" that a slide will fit within.
3. Construct a boxlike frame that will snugly fit all the square frames and is about 45 centimeters long. Leave the top of this frame open for now. Fasten the flashlight frame to one end of the box with the bulb pointing into the box. Attach the concave lens to the other end.
4. Insert the slide frame into the box frame in front of the flashlight. Insert the convex lens in the middle, between the slide holder and the concave lens. Don't glue this lens into place.
5. Decide adjust the convex lens from inside the projector box for focusing. Cut a long channel into the box bottom and glue a dowel stick onto the bottom of the lens so you can slide it back and forth. Or, leave the top of the frame open so you can move the lens by hand.
6. Make a hole in the top of the box right over the slide holding piece. It should be just big enough to insert and remove a slide within the holder.
7. Insert a slide into the projector and turn the flashlight on. The image of the slide should project onto the wall.
Tags: concave lens, convex lens, frame open, image slide, insert remove, Insert slide